All GSM service provider uses KPI to monitor their Quality Of Service (QOS) performance. Report generated from OMCR terminal & customer feedback are considered in further network improvement activity. RF optimization and drive test is the tool to keep continue watch on network QOS .In this paper some practical cases and solutions are adopted to improve the network QOS during drive test & post processing. Major QOS parameter Handover, call drop, congestion, interference reasons and solutions are discussed drive test tool Ascom TEMS 10.2.1 is used to perform drive test if optimization done continuously it will attract more and more customers due to service satisfaction.